[PATCH 5/6] KVM: Disallow all flags for KVM-internal memslots

[Sean Christopherson <seanjc@google.com>]

Disallow all flags for KVM-internal memslots as all existing flags require
some amount of userspace interaction to have any meaning.  This will allow
moving the flags checking from __kvm_set_memory_region() to
kvm_vm_ioctl_set_memory_region() without creating a hole where a KVM bug
could silently succeed and create a bogus memslot.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/kvm/kvm_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 42ec817d6a7e..84fcb20e3e1c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2104,6 +2104,9 @@ int kvm_set_internal_memslot(struct kvm *kvm,
 	if (WARN_ON_ONCE(mem->slot < KVM_USER_MEM_SLOTS))
 		return -EINVAL;
 
+	if (WARN_ON_ONCE(mem->flags))
+		return -EINVAL;
+
 	return  kvm_set_memory_region(kvm, mem);
 }
 EXPORT_SYMBOL_GPL(kvm_set_internal_memslot);
-- 
2.46.0.rc2.264.g509ed76dc8-goog